<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style>
			div{
				width: 180px;
				height: 180px;
				background-color: lightblue;
				line-height: 180px;/*行高一定要和高一样上下才会居中*/
				text-align: center;/*左右居中*/
			}
		</style>
	</head>
	<body>
		<div>
			我要居中
		</div>
	</body>
</html>
